1. Field of the Invention
The present invention is a display device that can control a viewing angle of a display panel for privacy protection or data preservation of users of the display device or a data terminal, and a driving method thereof. More particularly, the described technology relates generally to a display device for privacy protection that can limit readability from a side view without controlling colors or adding interference pixels to disturb readability in the display panel of the display device of another person, and a driving method thereof.
2. Description of the Related Art
Recently, users of mobile display devices or data terminals such as a portable phone, a personal digital assistant (PDA), and a computer have required data protection against another person, excluding themselves for privacy protection.
Responding to requests such as confidential disclosure and security for data terminals, a display device of the data terminal supports not only a normal viewing angle mode but also a narrow viewing angle mode.
As a method for satisfying a viewing angle control request, a dual viewing angle mode liquid crystal panel having an additional interference sub-pixel has been suggested. A double-structured liquid crystal panel may be an example of a viewing angle control mode liquid crystal panel.
The double-structure liquid crystal panel is formed of a normal panel where color pixels are formed and an interference panel disposed at an upper portion of the normal panel and having interference sub-pixels. The normal panel is used for displaying an image and the interference panel blocks light transmitted toward a side of the panel. The double-structure liquid crystal panel can change a viewing angle of an image by blocking light toward the side using the interference panel.
A viewing angle controllable liquid crystal display device including the double-structure liquid crystal panel selectively drives the interference panel to realize a wide viewing angle mode and a narrow viewing angle mode. That is, the liquid crystal display turns on and turns off the interference panel according to a viewing angle mode.
However, the double-structure liquid crystal panel is unproductive because it requires an additional process, and luminance of an image is significantly reduced because external light needs to pass a doubled layered liquid crystal layer. Further, the double-structure liquid crystal panel is increased in thickness and weight.
As another type of the liquid crystal panel in the viewing angle control mode, a liquid crystal panel using a region division method has been suggested. In the liquid crystal panel, normal color pixels and interference sub-pixels are arranged on the same plane. In the liquid crystal panel using the region division method, color pixels respectively include red, green, and blue normal sub-pixels and interference sub-pixels. Since the interference sub-pixels and the normal color sub-pixels are arranged on the same plane, the thickness and the weight of the liquid crystal panel are not increased. In addition, the liquid crystal panel using the region division method can control a viewing angle with one liquid crystal layer so that decrease of light amount and deterioration of luminance and color purity can be prevented.
However, the viewing angle control mode panel should drive the interference sub-pixels in addition to an existing driving method so that a driving circuit becomes complicated and manufacturing cost is increased.
Thus, in development of a viewing angle controllable display panel, a study for a display panel for privacy protection using a simple driving method without changing luminance of an image and adding an additional manufacturing process is required.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.